\section{Subsystem decomposition}
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		\begin{figure}[!ht]
		\includegraphics{img/subsystemdecomp.png}
		\caption{Subsystem decomposition}
		\end{figure}
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	The system consists of the following subsystems:
	\begin{itemize}
	\item \textbf{CalendarViewSubsystem}: A subsystem concerned with all user interface of the system. Its components are both View and Controller from our architectural model-view-controller pattern.
	\item \textbf{CalendarSubsystem}: Responsible for further communication with the Model - separates the CalendarViewSubsystem from program logic. Also a logical entity for storing calendar-specific settings such as time zones.
	\item \textbf{AppointmentSubsystem}: Responsible for all manipulation of Appointments.
	\item \textbf{AuthorizationSubsystem}: Responsible for authorization for persistent methods of the system. For example, it determines whether a user can store changes on the server or send invitations to others.
	\item \textbf{InvitationSubsystem}: Responsible for invitations to other users.
	\item \textbf{StorageSubsystem}: Responsible for persistent storage.
	\item \textbf{DatabaseSubsystem}: Responsible for storage in a Relational Database Management System (RDMS).
	\end{itemize}